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Persistent infarct hyperintensity on diffusion-weighted imaging late after stroke indicates heterogeneous, delayed,

Carly S Rivers1, Joanna M Wardlaw, Paul A Armitage

  • 1Division of Clinical Neurosciences, Western General Hospital, Edinburgh, UK.

Stroke
|April 29, 2006
PubMed
Abstract

Insights

Persistent diffusion-weighted MRI (DWI) hyperintensity after stroke indicates different infarct evolution and suggests ongoing ischemia. This finding correlates with worse outcomes and delayed perfusion normalization.

Area of Science:

  • Neuroimaging
  • Stroke Medicine
  • Radiology

Background:

  • Diffusion-weighted MRI (DWI) can show persistent hyperintensity in stroke infarcts at 1 month.
  • This late hyperintensity may indicate a different infarct evolution pathway.

Purpose of the Study:

  • To investigate if late DWI hyperintensity reflects distinct infarct evolution compared to isointense lesions.
  • To compare patient characteristics and MRI findings between groups.

Main Methods:

  • Prospective recruitment of ischemic stroke patients.
  • Serial DWI and perfusion-weighted MRI (PWI) at multiple time points.
  • Assessment of functional outcome using the Rankin Scale at 3 months.

Main Results:

  • 64% of patients showed persistent DWI hyperintensity at 1 month, predominantly in white matter.
  • These patients had lower baseline apparent diffusion coefficient ratio (ADCr) and prolonged ADCr reduction.
  • Delayed normalization of mean transit time and cerebral blood flow ratios were observed, alongside more severe initial stroke and worse 3-month outcomes.

Conclusions:

  • Late DWI hyperintensity highlights stroke injury heterogeneity and suggests ongoing ischemia.
  • Lower baseline ADCr precedes delayed perfusion normalization, indicating impaired reperfusion due to cell swelling.
  • Further research is needed to explore mechanisms and potential subacute interventions.

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